Trifluoroethylene (HFO-1123), which has a low global warming potential (GWP), is greatly expected in recent years as a new refrigerant which may replace difluoromethane (HFC-32) and 1,1,1,2,2-pentafluoroethane (HFC-125) which are greenhouse gases.
In this specification, abbreviated names (e.g. refrigerant numbers) of halogenated hydrocarbon compounds are described in brackets after the compound names. As the case requires, the abbreviated names are employed instead of the compound names.
Heretofore, as a process for producing HFO-1123, a process of using as a material 1,1,1,2-tetrafluoroethane (HFC-134a) which is a relatively inexpensive material has been known. For example, Patent Documents 1 and 2 disclose a process of subjecting HFC-134a to dehydrofluorination using a metal fluoride or a metal oxide as a catalyst to obtain HFO-1123.
However, by the production process disclosed in Patent Documents 1 and 2, since the reaction is conducted in a state where a large amount of nitrogen is mixed with HFC-134a so as to increase the degree of conversion of HFC-134a, nitrogen is contained in a large amount in the formed gas obtained after completion of the reaction (for example, outlet gas from the reactor). Accordingly, the content of the desired HFO-1123 is low in the formed gas, and the productivity is not satisfactory high. Further, since nitrogen is contained in a large amount in the formed gas, a load in the subsequent process such as purification of HFO-1123 and recovery of HFC-134a and nitrogen tends to be heavy, utility costs such as electricity are high, and large facilities are required for the purification and recovery.
Accordingly, to produce HFO-1123 useful as a new refrigerant which replaces greenhouse gases using HFC-134a which is an inexpensive material, an efficient production process with an improved degree of conversion of HFC-134a and with high productivity has been desired.